The phone is working pretty well so far. It's definitely a lot thinner and lighter. The display is extremely clear and bright. The biggest thing I've noticed so far is that some actions require going through menus more than I would like, but I'm starting to find shortcuts through most of them.

I didn't have any problems upgrading the firmware from the SGH-T809 to the SGH-D820. I'll have to keep watching GSMArena and HowardForums for more firmware upgrade.